This invention relates generally to reaction chamber isolation check valves, and more particularly to a combustion isolation check valve for use adjacent a precombustion chamber of a gaseous fuel internal combustion engine.
In one class of internal combustion engines, gaseous fuel is supplied from one of a variety of sources, such as natural gas or gas produced from a landfill. While the chemical content of these sources of gaseous fuel can vary widely, they typically include substantial amounts of methane which is suitable for burning in gaseous fuel internal combustion engines. Depending to some extent upon the source, engineers have observed that some of the additional components of the gaseous fuel reveal themselves as solid deposits that are produced during combustion within the engine. In some instances, these solid deposits within the engine can cause inadequate valve sealing, which in turn can cause engine malfunctions, such as misfiring.
In an effort to reduce exhaust emissions from gaseous fuel type engines, there have been efforts to burn leaner gaseous fuel/air mixtures. In order to burn these leaner mixtures, some engines include a precombustion chamber, in fluid communication with a main combustion chamber. Typically, in these engines a rich mixture is placed in the precombustion chamber and a much leaner mixture in the main combustion chamber. Ignition of the rich mixture in the precombustion chamber is the means by which the lean mixture in the main combustion chamber is ignited. While this precombustion chamber concept has proved effective in reducing exhaust emissions in gaseous fuel type engines, the deposit of solids in and on the valve that separates the precombustion chamber from its fuel supply can cause engine misfiring.
In most of these systems, a simple ball check valve separates the precombustion chamber from its fuel supply. These systems are designed such that compression and combustion pressure hold the ball valve against its seat in a closed position to isolate the precombustion chamber from its fuel supply during the combustion event. For a number of reasons, including the deposit of solids on the valve seat and other possible reasons such as pressure wave dynamics and other reasons not fully understood, these ball check valves do not always seal adequately. This can allow combustion gases to travel up into the fuel supply passage. This in turn can cause engine misfiring.
The present invention is directed to these and other problems associated with combustion isolation check valves, especially as they relate to gaseous fuel type engines.
A combustion isolation check valve includes a valve body with a conical valve seat that defines an inlet and an outlet. A valve member is positioned in the valve body between the inlet and the outlet, and is moveable between an open position and a closed position. The valve body and the valve member define a fluid passage that fluidly connects the inlet to the outlet when the valve member is in its open position. The valve body and the valve member substantially fluidly isolate the valve seat from the outlet when the valve member is in its closed position. In one aspect of the invention, the inlet of the valve body is connected to a source of fuel, and the outlet of the valve body is fluidly connected to a precombustion chamber within an internal combustion engine.